Genesis 46:2

And God spake unto Israel in the visions of the night
He appeared to Jacob as he lay upon his bed in the night season, and with an articulate voice spoke to him as follows: and said, Jacob, Jacob:
not "Israel", the more honourable name he had given him, but Jacob, putting him in mind of his former low estate; and doubling this name, either out of love and affection to him, as Jarchi intimates; or rather in order to awake him, at least to stir up his attention to what he was about to say to him: and he said, here [am] I;
signifying his readiness to hearken to him in what he should say to him, and to obey him in whatsoever he should command him.